This project is designed to continue our studies of immunopathologic mechanisms in selected cutaneous diseases including: the vesiculobullous skin diseases (the pemphigus group, the pemphigoid group, dermatitis herpetiformis, and erythema multiforme), cutaneous forms of lupus erythematosus, cutaneous vasculitis and chronic urticaria. Specifically, we will continue studies of the role of the complement system, especially the role of control proteins (C3b inactivator and Beta 1H globulin) and the terminal proteins (C8 and C9) in the bullous diseases. Studies of immune complexes, including detection, isolation, composition and characterization, are a major aspect of our proposed studies and will be conducted in all of the disease groups mentioned above. Little is known regarding the role of various lymphocytes or lymphocyte function in vesiculobullous skin diseases. These parameters will also be investigated. We will continue to isolate and further purify cutaneous antigens as they will be utilized in many of the proposed investigations.